how map 2d grid points (x,y) onto sphere as 3d points (x,y,z)

Question

I have a set of 2d grid points (x,y) that I want to map/project onto a sphere as 3d points (x,y,z).

I realize there will be some warping towards the poles as abs(y)

Answer 1

I suppose that your (x,y) on the sphere are latitude, longitude.

If so, see http://tutorial.math.lamar.edu/Classes/CalcII/SphericalCoords.aspx.

There:

phi = 90 degree - latitude

theta = longitude

rho = radius of your sphere.